JP4354294B2 - Gateway device connected to a plurality of networks having different network segments, and program and method for transferring IP packet - Google Patents

Description

  The present invention relates to a gateway device for bidirectionally transferring a message between at least two networks.

  A service providing device that can provide services such as audio / video (A / V) information is connected to an external network and may function as a gateway device. In this case, in order to use the service of the A / V device, the mobile device on the external mobile network directly accesses the service providing device and uses the service.

  In addition, such a service providing device may be connected to a separate gateway device connected to an external network via a home network. In this case, in order for the mobile device on the external mobile network to use the service of the A / V device, setting such as port forwarding is performed in advance in the gateway device, and access from the mobile device is allowed to It must be set in advance so that it can be transferred to the device.

JP 2001-308934 published on November 2, 2001 by Okuyama describes a communication control device, and a predetermined processing request is issued from a client device to an address storage device in the device. In response to an instruction from the server device, the local address of the server device and the port number in the local address are converted into the global address and the port number in the global address. It is stored in association with the port number in the local address. Connections can be automatically established even for server devices to which private local addresses and port numbers are set.
JP 2001-308934 A

  For example, since there is a difference between a global IP address and a private IP address, and security settings on the gateway such as a packet filter, a mobile device accesses a home network and uses a service of the device on the home network in advance. Settings such as address translation and port forwarding must be made. However, if port forwarding or the like is set even when such a service is not used, the devices in the home network are exposed to the risk of unauthorized access from the outside. It is cumbersome for the user to make such settings each time such a service is used.

  It is advantageous for the inventors to respond to an access from a device on the external network, and for the gateway to provide the device with available services of the device on the home network as a WWW service in a secure form. Recognized.

  An object of the present invention is to provide a gateway device that enables a service provided by a device on one network between at least two networks having different network segments to be used by a device on the other network. Is to realize.

According to a feature of the present invention, an IP having a header portion and a payload portion via a first and second network in which network segments including the first and second networks are connected to a plurality of different networks. gateway device for transmitting and receiving packets, a first address for a first network, the second and a second address for the network, the third through the first network and information providing means for receiving the first IP packet representing the search request information resource includes a second device address in the header portion thereof a third address as a source, the first representing the search request in response to the IP packet, the representative of the search request information resource includes in its header portion the second address as a source through the second network Sends the IP packet through the second network, the first containing a fourth address of the second represents the available resources of the third device on the network that the third device search means for receiving the third IP packet including the first resource identifier to the payload portion, the third address, the fourth address and the first resource identifier in association with each other stores Storage means. The information providing means, reads the first resource identifier from the storage means, the first resource identifier thus read out second resource for a first network including the first address rewriting the identifier, whereby the fourth address in the first resource identifier rewriting its first address, then the contain and third of the payload portion thereof a second resource identifier a fourth IP packet includes in its header portion a address as a destination via the first network transmits to the second device. The gateway device further a first network a fifth IP packet includes in its header portion the first address includes the gateway device to the header portion thereof a third address as the source as a destination when receiving from the second device via its included in the header portion thereof a 5 IP packet that second address to include in the header portion as a source thereof the fourth address of the destination rewriting the sixth IP packet for the second network, where the fifth in the third packet addresses the second of the rewritten address and the fifth in the packet that the first rewritten address to the fourth address, then the first 6 IP packets to the third device having a desired information resources via the second network Comprising a transfer means for feeding.

According to another feature of the invention, an IP packet having a header portion and a payload portion via at least first and second networks connected to at least first and second networks having different network segments. gateway device for transmitting and receiving, the gateway device includes a first address for a first network and a second address for that second network regularly its second network sends IP packets representing the search request information resource includes in its header portion the second address as a source via, through its second network, available on that second network response IP packetized including information resource identifier including the address of the available device represents the available resources of the device for the payload part Search means for receiving bets, and the address of its available devices, storage means for storing in association with each other and the information resource identifier, the third address through the first network first and comprising an information providing unit for receiving the first IP packet representing the two devices search request information resource includes in its header portion the third address as a source, a. When the gateway device receives the first IP packet, the information providing means in association with the address and the information resource identifier of the available devices in the third list form the address of store, the second first resource identifier including a fourth address of the information available represent resources that third device of a third device available on the network from the storage means reading, rewriting the first resource identifier thus read out to the second resource identifier for a first network including the first address, the fourth in the case the first resource identifier address rewriting to its first address, then include the second resource identifier to the payload portion in a list and the header portion that third address as a destination of A fourth IP packet including through the first network transmits to the second device.

  The present invention also relates to a program for realizing the information processing apparatus described above.

  The present invention also relates to a method for realizing the information processing apparatus described above.

  According to the present invention, a service provided by a device on one network between at least two networks having different network segments is used by a device on the other network while preventing unauthorized access. Is possible.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings, similar components are given the same reference numerals.

  FIG. 1 shows a UPnP (Universal Plug and Plug) as a network service providing apparatus interconnected via an internal network (internal NW) 10 such as a local area network (LAN) in a home according to an embodiment of the present invention. Play) A / V content service gateway device 100 and audio and / or video (A / V) devices 220, 240 and 260, and the external network 50 (external NW) to which the gateway device 100 is connected. 1 shows a schematic system including external information processing terminals (external terminals) 420 and 440 as network service utilization devices. The network segments of the internal network 10 and the external network 50 are different from each other. In addition to the internal network 10 and the external network 50, the gateway device 100 is connected to another network to which another network service providing device is connected and / or another network to which another network service using terminal is connected. It may be connected via a network interface. The external network 50 may include the Internet, ISDN, public telephone network (PSTN), and mobile radio communication network. Devices connected to the internal network 10 and the external network 50 are assigned IP addresses in the same or different address space. Here, IP addresses in different address spaces are assigned to devices connected to the internal network 10 and the external network 50, and private IP addresses are assigned to devices connected to the internal network 10. Assume that a global IP address is assigned to a device to be connected.

  The gateway device 100 is always connected to the external network 50 through, for example, an optical fiber, an ADSL, an ISDN line, a dedicated line, or the like. The A / V devices 220, 240, and 260 are, for example, a personal computer (PC) having an A / V recording / playback editing function, an A / V and text file server, an A / V recording / playback device, or audio and visual. It may be a home monitoring system. The A / V devices 220, 240, and 260 may be replaced with information processing devices that provide information services other than audio / video. The external information processing terminal 420 can be connected to the gateway device 100 via the external network 50. The external information processing terminal 440 can be connected to the gateway apparatus 100 on the external network 50 via the radio base station (AP) 52 of the mobile radio communication network. The external information processing terminals 420 and 440 may be fixed or mobile information processing terminals such as a notebook PC, a PDA (Personal Digital Assistant), or a mobile phone.

The gateway device 100 relays communication between the external information processing terminals 420 and 440 and the A / V devices 220, 240 and 260 through the internal network 10 and the external network 50 in accordance with the Internet protocol (IP). The gateway apparatus 100 makes service information and services provided by the A / V devices 220, 240, and 260 on the internal network 10 available to the external information processing terminals 420 and 440 on the external network 50.

  The global IP address for the external network 50 of the gateway device 100 is typically dynamically allocated by an Internet service provider (ISP), but may be fixedly allocated. When a new global IP address is assigned, gateway apparatus 100 notifies external information processing terminals 420 and 440 of the global IP address at a predetermined timing. The external information processing terminals 420 and 440 use the IP address, port number, and other information to access the A / V devices 220, 240, and 260 via the gateway device 100.

  The private IP addresses for the internal network 10 of the gateway device 100 and the A / V devices 220, 240 and 260 are typically dynamically assigned by the gateway device 100, but may be fixedly assigned.

  FIG. 2 shows a more detailed configuration of the gateway device 100, the A / V devices 220 and 240, and the external information processing terminals 420 and 440. The gateway device 100 includes an internal network interface (internal NW I / F) 102 for the internal network 10 that is one network segment, and an external network interface (external NW I / F) for the external network 50 that is another network segment. ) 104, a network service information providing unit 120, an information search unit 122, an information analysis and conversion unit 124, an information management unit 126, a network service transfer information storage unit 128, and a network service transfer unit 130. Depending on the case, the network service discovery information storage unit 129 may be included. The components 120 to 128 and 130 may be implemented (implemented) on the processor 110 according to a program, or may be implemented in the form of hardware as an integrated circuit. The network interfaces 102 and 104 include a physical interface such as an RJ-45 connector used in the 100BASE-TX standard, and a virtual network interface as software such as a VPN (Virtual Private Network). .

The A / V devices 220 and 240 include network interface (NW I / F) 2 1 2 and 242, for example, network service providing units 2 1 4 and 244 that store and read A / V program content, respectively. Contains.

  The external information processing terminals 420 and 440 include network interface (NW I / F) 422 and 442, and network service utilization units 424 and 244, respectively, for presenting A / V program content, for example. The components 224, 244, 424 and 444 may be implemented on a processor according to a program, or may be implemented in the form of hardware as an integrated circuit.

  For example, in a UPnP service such as the UPnP A / V standard content directory service, UPnP A / V content directory service is included in the UPnP service information acquired from the A / V device via the network by the service using device. Detailed service information such as how to access is included. The content directory service information includes content information such as a content access method such as a content URL. The content information includes a content file name, and can be actually acquired by selecting one content file. The UPnP service is composed of a plurality of asynchronous communication procedures such that the subsequent communication procedure depends on the previous communication procedure in the communication between the service using device and the service providing device.

  However, normally, external devices on the external network and internal devices on the internal network cannot communicate directly using their global and private IP addresses. Generally, an internal device on an internal network uses a gateway device's NAT (Network Address Translation) or NAPT (Network Address Port Translation) support to set a private IP address and port number in an IP packet header to a global IP address of the gateway device. By rewriting the address and port number, communication with an external device on the external network can be started. However, even in this case, the external device cannot use the private URL included in the response message from the internal device to access the device or resource on the internal network associated with the URL.

  The gateway device 100 according to the embodiment of the present invention is an asynchronous device for UPnP service performed between external information processing terminals (hereinafter also simply referred to as external terminals) 420 and 440 and A / V devices 220, 240, and 260. In a plurality of communication procedures, the contents of the packet header, UDP header and payload are tracked, analyzed and converted for each IP packet transfer, and an advantageous relay transfer is executed.

  FIG. 3 shows a processing procedure of UPnP A / V content service provided to the external information processing terminal 420 by the A / V devices 220, 240 and 260 via the gateway device 100. IP packets including a predetermined message are asynchronously and sequentially exchanged between the external terminal 420, the gateway device 100, and the A / V device 220 in accordance with a four-step communication procedure according to the UPnP standard. Each of the A / V devices 220, 240, and 260 includes a hierarchical UPnP device information service unit 221, UPnP service information service unit 222, UPnP A / V content information service unit 223, and A / V content service. Part 224 is included.

  In FIG. 3, in the first stage I, in response to the user's request for acquiring A / V content, the external terminal 420 acts as an initiator of the A / V content acquisition request in step 503. A multicast IP packet representing a search request is transmitted via the network 50. The packet header of the multicast IP packet includes, for example, 239.255.255.250:1990 as the destination IP address: port number in accordance with the UPnP standard.

  When the gateway apparatus 100 receives the IP packet representing the search request, in step 504, the gateway apparatus 100 does not change the destination IP address, but the source global IP address in the IP packet header, for example, 164. xx. xx. xx is rewritten to the private IP address of the gateway device 100, for example, 192.168.0.1, and the rewritten multicast IP packet is transferred to the A / V devices 220, 240, and 260 via the internal network 10.

  In response to the reception of the rewritten multicast IP packet, the UPnP device information service unit 221 of each of the A / V devices 220, 240, and 260 that can respond thereto receives the IP packet Use of the A / V devices 220, 240, and 260 by using the destination gateway apparatus 100, the source A / V devices 220, 240, and 260, and the private IP address and port number of the UPnP device information service unit 221 in the header Payload a response message containing one or more private URLs (information resource identifiers) representing possible UPnP device information, eg device information such as routers, A / V content servers, A / V display devices, printers or facsimile machines It sends IP packets containing the return. The URL includes access means (for example, http, ftp, etc.), private IP addresses of the A / V devices 220, 240, and 260, a port number of the next UPnP service information service unit 222, URL identification, and the like.

  In response to receiving the IP packet including the response message, the gateway device 100, in step 506, the private IP addresses and ports of the destination gateway device 100 and the source UPnP device information service unit 221 in the IP packet header. The number is rewritten to the global IP address and port number of the destination external terminal 420 and the source gateway apparatus 100 that were the source of the multicast IP packet, and a plurality of private URLs representing the device information in the payload are Rewrite to global URL. The gateway device 100 generates a message including a list of the plurality of global URLs representing services currently available for transfer by merging (combining) the plurality of global URLs, and records the list in the storage unit 128. May be. The gateway device 100 further lists the identification of the UPnP device information service unit 221 of the A / V devices (220, 240, and 260) that did not send back the response IP packet as a service unit that is not currently providing a service. May be recorded in the storage unit 128. Next, the gateway device 100 transmits an IP packet including the rewritten URL in the payload to the external terminal 420. The gateway apparatus 100 includes in the payload of the IP packet a message including the plurality of global URLs representing the currently available service and the identification of the service unit that is not currently providing the service in the form of a list. May be. In these global URLs, the private IP addresses of the A / V devices 220, 240, and 260 and the port number of the UPnP device information service unit 222 are rewritten to the global IP address of the gateway device 100 and an unused port number. For example, the private URL “http://192.168.0.10:18080/UrlA” is rewritten to the global URL “http: //164.xx.xx.xx.yy: 5801 / UrlA”.

  Regarding the transmitted / received IP packet header, in gateway apparatus 100, the global IP address and port number of external terminal 420 that is the originator of the request, the global port number and private port number of gateway apparatus 100, and A / V The correspondence between the private IP addresses and port numbers of the devices 220, 240, and 260 is stored in the storage unit 128 in a list format as network service transfer information. Also, with respect to the URL in the IP packet payload, the correspondence between the private URL and the global URL, or the correspondence between the private IP address and port number in the private URL and the global IP address and port number in the global URL Are also stored in the storage unit 128 in a list format as part of the network service transfer information.

  In the second stage II, in step 507, the external terminal 420 selects a required URL from the rewritten URLs, and sets the global IP address and port number in the selected URL to the IP packet. A global IP packet that is included in the destination field in the header and that includes the UPnP service information URL acquisition request message in the payload is transmitted to the gateway device 100. That is, the destination includes the global IP address and port number of the gateway device 100. The URL acquisition request is described as, for example, “GET / UrlA” or “GET / http: //164.xx.xx.yy: 58001 / UrlA”.

  In response to the reception of the IP packet, the gateway apparatus 100 determines in step 508 the destination global IP address in the IP packet header and the destination according to the correspondence between the private URL stored in the storage unit 128 and the global URL. Rewrite the port number back to the private IP address and port number. When the destination global IP address and port number are included in the URL description in the payload, the gateway apparatus 100 similarly rewrites them with the private IP address and port number. Next, the gateway device 100 transfers the private IP packet including the rewritten destination to the corresponding UPnP service information service unit 222 of the A / V devices 220, 240 and 260.

  In response to the UPnP service information acquisition request message, the UPnP service information service unit 222 in step 509, UPnP service information of the A / V devices 220, 240, and 260, such as programs, files, IP connection services, and An IP packet including a response message including one or more private URLs representing an access method such as a path in the payload is transmitted back to the gateway apparatus 100 using the private IP address and port number in the IP packet header. . The URL includes the private IP addresses of the A / V devices 220, 240 and 260, and the port number and URL identification of the next UPnP A / V content information service unit 223.

  In response to the reception of the IP packet including the response message, gateway apparatus 100, in step 510, private IP addresses and ports of destination gateway apparatus 100 and source UPnP service information service unit 222 in the IP packet header. The number is rewritten to the global IP address and port number of the destination external terminal 420 and the source gateway apparatus 100 that were the source of the IP packet representing the URL acquisition request, and the UPnP in the payload as described above. A plurality of private URLs representing service information are rewritten to a plurality of global URLs. Next, the gateway apparatus 100 transmits an IP packet including a response message including the rewritten URL list in the payload to the external terminal 420.

  In a third stage III, in response to the user's selection of a specific URL in the global URL representing the list of content, ie, selection of specific UPnP service information, the external terminal 420, in step 511, selects that URL. The global IP address and the port number in the URL are included in the destination field in the IP packet header, and the global IP packet including the UPnP A / V content information acquisition request message in the payload is transmitted to the gateway device 100.

  In response to the reception of the IP packet, the gateway device 100 determines in step 512 the destination global IP address in the IP packet header and the destination according to the correspondence between the private URL and the global URL stored in the storage unit 128. Rewrite the port number with the private IP address and port number. When the destination global IP address and port number are included in the URL description in the payload, the gateway device 100 rewrites the private IP address and port number in the same manner. Next, the gateway device 100 transfers the private IP packet including the rewritten destination to the UPnP A / V content information service unit 223 of the A / V devices 220, 240, and 260.

  In response to the UPnP A / V content information acquisition request, the UPnP A / V content information service unit 223, in step 513, determines UPnP A / V content information of the A / V devices 220, 240, and 260, for example, program A response message including one or more private URLs representing the file name in the payload is transmitted back to the gateway apparatus 100 using the private IP address and port number in the IP packet header. The URL includes the private IP addresses of the A / V devices 220, 240 and 260, and the port number and URL identification of the next A / V content service unit 224.

  In response to receiving the IP packet including the response message, the gateway device 100 sets the destination IP address and the source private IP address and port number in the IP packet header to the global IP address and the port number in step 514 as described above. The port number is rewritten, and a plurality of private URLs representing the UPnP A / V content information in the payload are rewritten to a plurality of global URLs. Next, the gateway apparatus 100 transmits an IP packet including a response message including the rewritten URL list in the payload to the external terminal 420.

  In the fourth stage IV, in response to the user's selection of the specific URL in the global URL representing the A / V content information, that is, the selection of the specific A / V content, the external terminal 420 The global IP packet including the global IP address and port number in the selected URL is included in the destination field in the IP packet header, and the UPnP A / V content acquisition request message is included in the payload.

  In response to the reception of the IP packet, in step 516, gateway apparatus 100 determines the global IP address of the destination in the IP packet header according to the correspondence between the private URL stored in storage unit 128 and the global URL. Rewrite the port number with the private IP address and port number. When the destination global IP address and port number are included in the URL description in the payload, the gateway device 100 rewrites the private IP address and port number in the same manner. Next, the gateway device 100 transfers the private IP packet including the rewritten destination to the A / V content service unit 224 of the A / V devices 220, 240, and 260.

  In response to the acquisition request for the specific A / V content, the A / V content service unit 224 sends the corresponding specific A / V content files of the A / V devices 220, 240 and 260 in step 517. The IP packet included in the payload is transmitted back to the gateway apparatus 100 using the private IP address and port number in the IP packet header.

  In response to receiving the IP packet including the A / V content file, the gateway device 100 determines the destination and source private IP address and port number in the IP packet header in step 518 as described above. The global IP address and port number are rewritten, and an IP packet including a specific A / V content file in the payload is transmitted back to the external terminal 420.

  In the gateway apparatus 100, the information analysis and conversion unit 124 converts the private IP address: port number included in the URL in the payload of the response message from the A / V devices 220, 240, and 260 on the internal network 10 to the gateway. Global IP address of device 100: Rewrite to unused port number. Thereafter, when access is received from the external network to the same port number in the global IP address, the information analysis and conversion unit 124, according to the correspondence stored in the storage unit 128, the destination in the IP packet header IP address: Rewrite the port number and rewrite the URL in the payload.

  FIG. 4A illustrates network service transfer information stored in the storage unit 128. 4B shows the correspondence between the private URL including the private IP address and port number for the internal network 10 stored in the storage unit 128 and the global URL including the global IP address and port number for the external network 50. Is shown.

  For example, the global IP address of the external terminal 420 is “164.xx.xx.xx”, and the global IP address and the private IP address of the gateway device 100 are “164.xx.xx.yy” and “192.168 .. It is assumed that the private IP address of the internal A / V device 220 is “192.168.0.10”. The gateway apparatus 100 receives a destination multicast IP address “239.255.255.250:1900” from the external terminal 420 having the global IP address: port number “164.xx.xx.xx: 9999” on the external network 50. When the IP packet representing the device search request using is received, the information analysis and conversion unit 124 rewrites the source of the IP packet to the private IP address “192.168.0.1” of the gateway device 100. The information search unit 122 transmits the rewritten IP packet to the A / V devices 220, 240, and 260 on the internal network 10. Further, the information management unit 126 sets the entry number “000”, the global IP address “164.xx.xx.xx” of the external terminal 420 as the external source, and the global port number “1900” for transfer of the gateway device 100. "And the destination private IP address:" 239.255.255.250:1900 "as the port number and the last transfer time" 14: 52: 30.981 "transferred to the internal network 10 are written.

  When the information search unit 122 receives the response IP packet from the UPnP device information service unit 221 of the A / V devices 220, 240, and 260, the information analysis and conversion unit 124 sends the source “192. “168.0.10: 1900” is rewritten to “164.xx.xx.yy: 1900”, and the destination “192.168.0.1:9999” is rewritten to “164.xx.xx.xx: 9999”. The information management unit 126 writes “in operation” in the storage unit 128 as the state of the UPnP device information service unit 221 in the entry number “000”. The information management unit 126 may rewrite the private IP address of the entry number “000” with “192.168.0.10” of the transmission source. On the other hand, when the response IP packet is not received at a predetermined time, the information management unit 126 writes “stopped” in the storage unit 128 as the state of the UPnP device information service unit 221 in the entry number “000”.

  When the network service transfer unit 130 includes a private URL in the payload of the IP packet received from the internal network 10, the information analysis and conversion unit 124 uses the private IP address and port number therein as the gateway device. By rewriting to the global IP address and port number of 100, the private URL is rewritten to the global URL. As shown in FIG. 4B, the information management unit 126 records the correspondence between the private URL and the global URL in the storage unit 128 as part of the network service transfer information.

  For example, the gateway device 100 then sends the source global IP address: port number “164.xx.xx.xx: 9998” and the destination global IP address: port number “164” in the IP packet header from the external terminal 420 described above. .Xx.xx.yy: When receiving an IP packet representing a URL acquisition request including 58001 ”, the information analysis and conversion unit 124 receives the external source global IP address of the related entry number“ 000 ”and The private IP address and the port number are referred to, and the correspondence between the private URL and the global URL is referenced to check the consistency between the current received IP packet and the previous transmitted and received IP packet. The source is the private IP address of the gateway device 100. Res: Port number “192.168.0.1: 192.168.0.1:18000” and “192.168.0.10: UPnP service information service unit 222 of A / V device 220 corresponding to the destination: Rewrite to 18080 ". The network service transfer unit 130 transmits the rewritten IP packet to the UPnP service information service unit 222.

  The information management unit 126 includes the entry number “001”, the global IP address “164.xx.xx.xx” of the external terminal 420 as the external source, the global port number “58001” for transfer of the gateway device 100, and Destination private IP address: port number “192.168.0.10:18080”, last transfer time “14: 52: 40.981” transferred to internal network 10 and related entry number “000” are written. When the network service transfer unit 130 receives the response IP packet from the UPnP device information service unit 221, the information analysis and conversion unit 124 sends the source “192.168.0.10: 18080” in the response IP packet header. Is rewritten to “164.xx.xx.yy: 58001”, and the destination “192.168.0.1:18000” is rewritten to “164.xx.xx.xx: 9998”. The information management unit 126 stores “in operation” in the storage unit 128 as the state of the UPnP device information service unit 221.

  Thereafter, the information analysis and conversion unit 124 rewrites the IP address and port number of the associated subsequent IP packet based on this network transfer information until a predetermined time elapses from the final transfer time. In this way, the network service transfer information with the entry numbers “003” to “005” is recorded.

In the stored network service information, when the corresponding transfer is not performed for a predetermined time or more after the final transfer time, the entry is invalidated and subsequent transfer is prohibited. In order to perform the same transfer again, the external terminal 4 20, it is necessary to search for the network service again. By invalidating the transfer due to the elapsed time, unnecessary access to internal network resources from the outside is prevented.

  FIG. 5 shows a flowchart for device search executed by the gateway apparatus 100 in response to a request from the external information processing terminal 420.

  First, the external terminal 420 transmits a multicast IP packet representing a device search request on the external network 50 to the gateway apparatus 100 via the base station 52 in accordance with a user operation.

  In step 602 of FIG. 5, the network service information providing unit 120 of the gateway apparatus 100 receives a multicast IP packet representing a device search request from the external terminal 420 via the external network interface 104.

  In step 606, the network service information providing unit 120 passes the IP packet to the information search unit 122 and requests device search. In response to the request, the information search unit 122 causes the information analysis and conversion unit 124 to rewrite the IP packet header as described above, and the A / V on the internal network 10 via the internal network interface 102. A multicast IP packet representing a device search request is forwarded to the devices 220, 240 and 260. In response to the request, each of the UPnP device information service units 221 of the A / V devices 220, 240, and 260 responds with a response IP packet including a URL for acquiring UPnP service information as corresponding UPnP device information in the payload. Is sent back to the gateway device 100. The URL includes a private IP address, a port number, and an information resource identifier, such as “http://192.168.0.10:18080/UrlA” and “http://192.168.0.12: 8080 / UrlD ".

  In step 608, the information search unit 122 determines whether a response IP packet has been received. If no response IP packet has been received, the procedure proceeds to step 630. When the response IP packet is received, in step 618, the information search unit 122 passes the response IP packet to the information analysis and conversion unit 124. The information analysis and conversion unit 124 parses (parses) the header and payload of the response IP packet, extracts the private IP address, port number, and URL, and passes them to the information management unit 126. The information management unit 126 searches the network service transfer information in the storage unit 128 for an item that matches the URL.

  In step 622, the information management unit 126 determines whether or not there is an item that matches the URL in the network service transfer information. If it is determined that there is no matching item, in step 624, the information management unit 126 adds the URL and related items to the network service transfer information in the storage unit 128. If it is determined that there is a matching item, in step 626, the information management unit 126 takes out an item related to the URL and passes it to the information analysis and conversion unit 124. The information search unit 122 may further extract URLs of other service units (221 to 224) that are not currently provided and stored in the storage unit 128 via the information management unit 126 and add them to the payload.

In step 62 6, the information analysis and the conversion unit 124 rewrites the IP packet header, as described above, by rewriting the private URL in the payload to the global URL, so the rewritten IP packet service information retrieval unit 122 To the network service information providing unit 120. In step 628, the network service information providing unit 120 transmits the IP packet including the rewritten URL in the payload to the external terminal 420 that is the source on the external network 50 via the external network interface 104. In this case, the network service information providing unit 120 integrates a plurality of URLs in one or a plurality of IP packets in a plurality of response IP packets, and includes a list of the plurality of integrated URLs in the payload 1 One IP packet may be transmitted to the external terminal 420.

In step 630, the information management unit 126 refers to the network service transfer information in the storage unit 128, and determines a predetermined time from the last transfer time when the previous IP packet from the source external terminal 420 was transferred to the internal network 10. Determine if it has passed. If the predetermined time is determined to have elapsed, the procedure exits the routine of FIG. If it is determined that the predetermined time has not elapsed, the procedure returns to step 608.

  FIG. 6 shows a flowchart for transferring the IP packet executed by the gateway apparatus 100 in response to the reception of the IP packet representing the URL acquisition request from the external information processing terminal 420.

  The external terminal 420 parses information including one or more URLs in the payload of the IP packet received from the gateway device 100, and a specific one URL in the one or more URLs corresponding to the user request. Select. The external terminal 420 transmits to the gateway apparatus 100 an IP packet that includes the IP address and port number of the selected URL in the IP packet header and includes a message requesting acquisition of the URL in the payload.

  In step 704 of FIG. 6, the network service transfer unit 130 receives an IP packet representing a request for acquiring the URL from the external network 50 via the external network interface 104.

  In step 706, the network service transfer unit 130 passes the received IP packet to the information analysis and conversion unit 124. The information analysis and conversion unit 124 parses the received IP packet, extracts the source global IP address and the destination global URL in the packet header, and passes them to the information management unit 126. The information management unit 126 refers to the network information service transfer information in the storage unit 128 to check whether the transmission source and destination are recorded. In step 706, the information management unit 126 determines whether or not the source and destination have been recorded. If it is determined that either the source or destination has not been recorded, in step 710, the network service transfer unit 130 discards the received IP packet. Thereafter, the procedure exits the routine of FIG.

In the case where they are determined to be recorded, in step 712, the information management unit 126, referring to the recorded network service information storage section 12 8 from the last (previous) transfer time to the current Find the elapsed time. In step 714, the information management unit 126 determines whether a predetermined time has elapsed. If it is determined that the predetermined time has elapsed, in step 716, the information management unit 126 deletes the corresponding transfer information in the storage unit 128 of the network information service transfer information. Thereafter, the procedure exits the routine of FIG. If it is determined that the predetermined time has not elapsed, the information management unit 126 adds or updates the corresponding transfer information such as the last transfer time in the storage unit 128 in step 718.

  In step 720, the information analysis and conversion unit 124 rewrites the header of the IP packet as described above, and rewrites the URL when the URL is included in the payload. The network service transfer unit 130 transfers the rewritten IP packet to the corresponding service units of the A / V devices 220, 240 and 260 on the internal network 50. Thereafter, the procedure exits the routine of FIG.

  FIG. 7 is a flowchart for transfer of response IP packets executed by the gateway device 100 when receiving response IP packets from the A / V devices 220, 240 and 260 in response to requests from the external terminals 420 and 440. Show.

  In response to requests from external terminals 420 and 440, UPnP service information service unit 222, UPnP A / V content information service unit 223 or A / V identified by the destination URL received by A / V devices 220, 240 and 260 The V content service unit 224 transmits a response IP packet including a plurality of URLs or content files representing UPnP service information, UPnP A / V content information, or content in the payload to the gateway apparatus 100 and returns it.

  In step 804, the network service transfer unit 130 receives a response IP packet including the next URL or content file in the payload from the internal network 10 via the internal network interface 102.

In step 806, the network service transfer unit 130 passes the required part of the response IP packet to the information analysis and conversion unit 124. The information analysis and conversion unit 124 parses the IP packet, extracts the source and destination private IP addresses and port numbers in the packet header, and passes them to the information management unit 126. The information management unit 126 refers to the network information service transfer information in the storage unit 128 to check whether the source and destination global IP addresses and port numbers of IP packets representing requests of the corresponding external terminal have been recorded. In step 80 8, the information management unit 126 determines whether the source and / or destination or recorded. If it is determined that it has not been recorded, the procedure exits the routine of FIG. If it is determined that it has already been recorded, the procedure proceeds to step 618. Steps 618-628 are the same as in FIG. 4 and will not be described again. After step 628, the procedure exits the routine of FIG.

  8A and 8B are different from FIG. 5 and show another flowchart for device search executed by the gateway apparatus 100 in response to a request from the external information processing terminal 420. By this device search, the operating state of the service providing apparatus can be provided to the service using apparatus. 8A and 8B, steps 602, 606-608 and 618-630 are similar to those of FIG. 5 and will not be described again.

  In step 604 after step 602, the network service information providing unit 120 causes the information management unit 126 to initialize the network service discovery information in the storage unit 129 via the information search unit 122. In step 612 after step 608, the information management unit 126 cooperates with the information analysis and conversion unit 124 in the response IP packet received from the UPnP device information service unit 221 of the A / V devices 220, 240, and 260. Referring to the information related to the UPnP device information service unit 221, the network service of the storage unit 129 stores items relating to the operating state of the UPnP device information service unit 221, such as the private IP address and port number, and the operating state “operating” Add to discovery information.

  FIG. 10 shows a list of network service discovery information stored in the storage unit 129. The network service discovery information includes the private IP address, port number, and current operating state of the network service A / V device 220 connected to the internal network 10.

  In step 632, the information management unit 126 acquires an uninspected item from the network service transfer information in the storage unit 128. In step 634, the information management unit 126 searches the network / service discovery information in the storage unit 129 for an item that matches the acquired item.

  In step 636, the information search unit 122 determines whether there is a response that matches the acquired item. If it is determined that there is a response that matches the acquired item, the procedure proceeds to step 642. If it is determined that there is no response that matches the acquired item, in step 638, the information management unit 126 sets the corresponding item in the transfer information to “stop state”. In step 642, the information search unit 122 determines whether all items have been inspected. If it is determined that all items have not been inspected, the procedure returns to step 632.

  If it is determined that all items have been inspected, in step 644, the network service information providing unit 120 uses the network service discovery information stored in the storage unit 129 to identify network services that are currently available and unavailable. A list is created, and an IP packet including the list in the payload is transmitted to the external terminal 220. Thereafter, the procedure exits the routine of FIGS. 8A and 8B.

  FIGS. 9A and 9B are a modification of FIGS. 8A and 8B, and show yet another flowchart for device search performed by the gateway apparatus 100.

  The flowcharts of FIGS. 9A and 9B do not include steps 602, 626, and 628 of FIG. 8A. The flowchart of FIGS. 9A and 9B begins at step 604. The flowchart of FIG. 5 is executed independently in parallel with FIGS. 9A and 9B. Steps 604-624 and 630-642 are similar to those of FIGS. 8A and 8B and will not be described again.

After step 642, in step 644, the procedure pauses for a predetermined time and then returns to step 632. In this way, the information search unit 122 detects the operating state of the A / V devices 220 to 240, that is, whether the A / V device 220 to 240 is operating or stopped periodically, periodically, or at a predetermined time interval. 129. A network service information providing unit 120, when receiving the multicast IP packets from the external terminal 4 20 and 4 40 representative of a request of searching a device at step 602 of FIG. 5, in step 628 of FIG. 5, which is the accumulated A response IP packet including, in the payload, a list including the operation status of the network service of the / V devices 220 to 240, that is, whether or not the service is usable, and a list including the plurality of integrated URLs. Transmit to external terminals 4 20 and 4 40.

Alternatively configuration, network service information providing unit 120, when receiving the multicast IP packets from the external terminal 4 20 and 4 40 representative of a request of search for the device, the network of A / V devices 220-240 that is the accumulated operating status of the service (URL), i.e., a response IP packet including the payload list that the service indicating whether available may be transmitted to the external terminal 4 20 and 4 40. In other words, in FIG. 5, after step 602, steps 606 to 626 and 630 are not executed, and in step 628, the response IP packet including the above list in the payload is transmitted to the external terminals 220 and 240. It may be.

  Referring to FIG. 3 again, the network service transfer unit 130 sends an IP packet representing a request for access to any of the service units 221 to 224 of the A / V devices 220 to 260 on the internal network 10 (step of FIG. 3). 507, 511, and 515) from the external terminal 420 via the external network 50, the service units (221 to 224) that are currently stopped in the network service operation information stored in the storage unit 128. ) And the A / V device providing the service is currently stopped, an IP packet including a message indicating that the A / V device providing the service is currently stopped. Alternatively, it may be transmitted to the external terminal 420 via the external network 50.

  The network service transfer unit 130 transmits an IP packet (steps 507, 511, and 515 in FIG. 3) indicating a request for access to any of the service units 221 to 224 of the A / V devices 220 to 260 on the internal network 10. When receiving from the external terminal 420 via the external network 50, the A / V device that provided the service is the currently operating A / V device in the network service operation information stored in the storage unit 128. If the corresponding service unit is currently stopped, an IP packet including a message indicating that the service is currently stopped may be transmitted to the external terminal 420 via the external network 50.

  The network service transfer unit 130 transmits an IP packet (steps 507, 511, and 515 in FIG. 3) indicating a request for access to any of the service units 221 to 224 of the A / V devices 220 to 260 on the internal network 10. When received from the external terminal 420 via the external network 50, the A / V device providing the service corresponds to the stopped A / V device in the network service operation information stored in the storage unit 128, and If the A / V device providing the service is currently stopped, the service unit includes a message requesting that the currently stopped A / V device be activated to use the service unit. An IP packet including a message indicating a request for access to the A / V device may be transmitted to the currently stopped A / V device.

  The embodiments described above are merely given as typical examples, and it is obvious to those skilled in the art to combine the components of each embodiment, and variations and variations thereof will be apparent to those skilled in the art. Obviously, various modifications may be made to the above-described embodiments without departing from the scope of the invention as set forth in the scope.

Regarding the embodiment including the above examples, the following additional notes are further disclosed.
(Supplementary note 1) A gateway device as a first device connected to a plurality of networks having different network segments including the first and second networks,
The gateway device has a first IP address for the first network and a second IP address for the second network;
Information providing means for receiving, via the first network, a first IP packet representing a search request for information resources including the third IP address as a source from a second device having a third IP address;
In response to the first IP packet representing the search request, the second IP packet representing the information resource search request including the second IP address as a source is transmitted via the second network; A first information resource identifier representing a usable information resource of a third device on the second network via the second network and including a fourth IP address of the third device; Search means for receiving a third IP packet;
Storage means for storing the third IP address, the fourth IP address, and the first information resource identifier in association with each other;
With
The information providing means reads the first information resource identifier from the storage means, and the read first information resource identifier includes the first IP address as the second information resource for the first network. Rewriting to an identifier, rewriting the fourth IP address in the first information resource identifier to the first IP address, then including the second information resource identifier and addressing the third IP address A fourth IP packet including as to the second device via the first network,
Further, when the gateway device receives a fifth IP packet including the third IP address as a source and including the first IP address as a destination from the second device via the first network. , Rewriting the fifth IP packet with a sixth IP packet for the second network including the second IP address as a source and the fourth IP address as a destination. Rewriting the third IP address in the packet to the second IP address and rewriting the first IP address in the fifth packet to the fourth IP address, and then changing the sixth IP packet to A gateway comprising transfer means for transferring to the third device having a desired information resource via the second network. Apparatus.
(Supplementary Note 2) The transfer means then represents the information resource available to the third device including the fourth IP address as a source and the second IP address as a destination. When a seventh IP packet including a third information resource identifier including an address is received from the third device via the second network, the seventh IP packet is transmitted to the first IP address. To the eighth IP packet including the third IP address as the destination and the fourth information resource identifier, and changing the fourth IP address in the seventh IP packet to the second IP packet. And rewriting the second IP address in the seventh IP packet to the third IP address, and then changing the eighth IP packet to the first IP address. The gateway device according to appendix 1, wherein the gateway device transfers data to the second device via a network.
(Supplementary Note 3) The first information resource identifier further includes a first port number of the third device for the second network, and the second information resource identifier further includes the first information in the gateway device. Contains an unused second port number for the network of
The gateway device transmits the fifth IP packet including the third IP address as a source and the first IP address and the second port number as a destination via the first network. When the second IP packet is received from the second device, the transfer means includes the second IP address as the source and the fourth IP address and the first port number as the destination. Rewriting to the sixth IP packet for the network, rewriting the third IP address in the fifth packet to the second IP address and the first IP in the fifth packet The address and the second port number are rewritten to the fourth IP address and the first port number, respectively, and then the sixth IP Transfer means for transferring Tsu bets to the third device having the available resources via said second network,
The gateway device according to claim 1, further comprising:
(Supplementary Note 4) The third IP address is used as a source until a predetermined time elapses after the sixth IP packet is last transferred to the third device via the second network. An eighth IP packet for the second network including the seventh IP packet including the first IP address as a destination and the second IP address as a source and including the fourth IP address as a destination The gateway according to appendix 1, wherein the eighth IP packet can be transferred to the second network through rewriting to the second network, but the transfer can be prohibited after the predetermined time has elapsed. apparatus.
(Supplementary Note 5) When the transfer unit receives an IP packet including an IP address other than the IP address stored in the storage unit as a source and / or destination via the first network, the IP packet The gateway device according to appendix 1, wherein the gateway device is not transferred via the second network.
(Additional remark 6) The said search means further transmits the IP packet which represents the search request | requirement of information resources including the said 2nd IP address as a transmission origin via the said 2nd network regularly, and the said 2nd network A response IP packet including an information resource identifier representing an available information resource of an available device on the second network and including an IP address of the available device via
The gateway device according to appendix 1, wherein the storage means further stores the IP address of the available device and the certain information resource identifier in association with each other.
(Additional remark 7) The said search means transmits the IP packet which contains the said 2nd IP address as a transmission origin further via the said 2nd network, and represents the search request | requirement of information resources, The said 2nd network A response IP packet including an information resource identifier representing an available information resource of an available device on the second network and including an IP address of the available device via
The storage means further stores the IP address of the available device and the certain information resource identifier in association with each other in a list format,
The information providing means further reads the certain information resource identifier from the storage means, and uses the read certain information resource identifier as another information resource identifier for the first network including the first IP address. Rewriting, rewriting the IP address in the certain information resource identifier to the first IP address, and integrating the second information resource identifier with the other information resource identifier to generate integrated information The gateway device according to appendix 1, wherein the fourth IP packet including the integrated information in a list format is transmitted to the second device via the first network.
(Additional remark 8) When the said search means stores the information showing the operating state of the information resource which can be utilized on the said 2nd network in the said storage means, and the information resource which was available in the past is not now available The gateway device according to appendix 1, wherein the gateway device stores information indicating that an operating state of an information resource that has been available in the past is currently unavailable.
(Supplementary Note 9) When the transfer unit receives an IP packet representing a request for access to a desired information resource on the second network from the second device via the first network, the transfer unit The information resource corresponds to the information resource currently stopped in the operation information stored in the storage means, and another device that provided the desired information resource is currently stopped. To the second device via the first network, an IP packet including a message indicating that the other device that provided the information resource is currently stopped The gateway device described.
(Supplementary Note 10) When the transfer means receives an IP packet representing a request for access to a desired information resource on the second network from the second device via the first network, the transfer means If another device that provided the information resource corresponds to the currently operating device in the operation information stored in the storage means, and the desired information resource is currently stopped, The gateway apparatus according to appendix 1, wherein an IP packet including a message indicating that the information resource is currently stopped is transmitted to the second apparatus via the first network.
(Supplementary Note 11) When the transfer means receives an IP packet representing a request for access to a desired information resource on the second network from the second device via the first network, If the device that provides the desired information resource corresponds to the stopped device in the operation information stored in the storage means, and the device that provides the desired information resource is currently stopped, Note that an IP packet including a message requesting to start a stopped device and make the desired information resource available is transmitted to the currently stopped device via the second network. The gateway device according to 1.
(Supplementary Note 12) The transfer of IP packets from the first network to the second network and the transfer of IP packets from the second network to the first network are performed asynchronously with each other. The gateway device according to attachment 1, wherein
(Supplementary note 13) The gateway device according to supplementary note 1, wherein communication between the first and second networks conforms to a UPnP standard.
(Supplementary note 14) A gateway device as a first device connected to at least first and second networks having different network segments,
The gateway device has a first IP address for the first network and a second IP address for the second network;
Periodically, an IP packet that represents the information resource search request including the second IP address as a source is transmitted via the second network, and is transmitted on the second network via the second network. Search means for receiving a response IP packet that includes an information resource identifier that represents an available information resource of the available device and includes an IP address of the available device;
Storage means for storing the IP address of the available device and the information resource identifier in association with each other;
Information providing means for receiving, via the first network, a first IP packet representing a search request for information resources including the third IP address as a source from a second device having a third IP address;
With
When the gateway device receives the first IP packet, the information providing means displays the third IP address in a list format in association with the IP address and the information resource identifier of the available device. Storing, from the storage means, a first information resource identifier representing an available information resource of a third device available on the second network and including a fourth IP address of the third device; Read, rewrite the read first information resource identifier to the second information resource identifier for the first network including the first IP address, and then the fourth information in the first information resource identifier Rewrites the first IP address to the first IP address, and then includes the second information resource identifier in a list format and the third IP address as the destination. The IP packets transmitted to the second device via the first network,
Further, when the gateway device receives a fifth IP packet including the third IP address as a source and including the first IP address as a destination from the second device via the first network. , Rewriting the fifth IP packet with a sixth IP packet for the second network including the second IP address as a source and the fourth IP address as a destination. Rewriting the third IP address in the packet to the second IP address and rewriting the first IP address in the fifth packet to the fourth IP address, and then changing the sixth IP packet to A gateway comprising transfer means for transferring to the third device having a desired information resource via the second network. Apparatus.
(Supplementary note 15) A program for transferring an IP packet for a gateway device as a first device connected to a plurality of networks including first and second networks having different network segments,
The gateway device has a first IP address for the first network and a second IP address for the second network;
Receiving a first IP packet representing a search request for an information resource including the third IP address as a source from a second device having a third IP address via the first network;
In response to the first IP packet representing the search request, the second IP packet representing the information resource search request including the second IP address as a source is transmitted via the second network; A first information resource identifier representing a usable information resource of a third device on the second network via the second network and including a fourth IP address of the third device; Receiving a third IP packet;
Storing the third IP address, the fourth IP address, and the first information resource identifier in a memory in association with each other;
Reading the first information resource identifier from the memory, rewriting the read first information resource identifier with a second information resource identifier for the first network including the first IP address, Rewriting the fourth IP address in the first information resource identifier to the first IP address, and then the fourth IP packet including the second information resource identifier and including the third IP address as a destination Transmitting to the second device via the first network;
When the fifth IP packet including the third IP address as a source and the first IP address as a destination is received from the second device via the first network, the fifth IP Rewriting the packet to a sixth IP packet for the second network that includes the second IP address as a source and the fourth IP address as a destination, wherein the third IP in the fifth packet The IP address of the second packet is rewritten to the second IP address, the first IP address in the fifth packet is rewritten to the fourth IP address, and then the sixth IP packet is transferred to the second network. Transferring to the third device having the desired information resource via
A program that can run to run.
(Supplementary Note 16) A method of transferring an IP packet in a gateway device as a first device connected to a plurality of networks having different network segments including a first and a second network,
The gateway device has a first IP address for the first network and a second IP address for the second network;
Receiving a first IP packet representing a search request for an information resource including the third IP address as a source from a second device having a third IP address via the first network;
In response to the first IP packet representing the search request, the second IP packet representing the information resource search request including the second IP address as a source is transmitted via the second network; A first information resource identifier representing a usable information resource of a third device on the second network via the second network and including a fourth IP address of the third device; Receiving a third IP packet;
Storing the third IP address, the fourth IP address, and the first information resource identifier in a memory in association with each other;
Reading the first information resource identifier from the memory, rewriting the read first information resource identifier with a second information resource identifier for the first network including the first IP address, Rewriting the fourth IP address in the first information resource identifier to the first IP address, and then the fourth IP packet including the second information resource identifier and including the third IP address as a destination Transmitting to the second device via the first network;
When the fifth IP packet including the third IP address as a source and the first IP address as a destination is received from the second device via the first network, the fifth IP Rewriting the packet to a sixth IP packet for the second network that includes the second IP address as a source and the fourth IP address as a destination, wherein the third IP in the fifth packet The IP address of the second packet is rewritten to the second IP address, the first IP address in the fifth packet is rewritten to the fourth IP address, and then the sixth IP packet is transferred to the second network. Transferring to the third device having the desired information resource via
A method comprising the steps of:

FIG. 1 illustrates a gateway device and an audio / video (A / V) device for UPnP A / V content service as a network service providing device interconnected via an internal network according to an embodiment of the present invention; 1 shows a schematic system including an external information processing terminal as a network service utilization device connected to an external network to which the gateway device is connected. FIG. 2 shows a more detailed configuration of the gateway device, A / V device, and external information processing terminal. FIG. 3 shows the processing procedure of the UPnP A / V content service provided to the external information processing terminal by the A / V device via the gateway device. FIG. 4 illustrates network service transfer information stored in the storage unit. FIG. 4B shows the correspondence between the private URL stored in the storage unit including the private IP address and port number for the internal network and the global URL including the global IP address and port number for the external network. ing. FIG. 5 shows a flowchart for device search executed by the gateway apparatus in response to a request from the external information processing terminal. FIG. 6 shows a flowchart for forwarding the IP packet executed by the gateway device in response to the reception of the IP packet representing the URL acquisition request from the external information processing terminal. FIG. 7 shows a flowchart for transfer of a response IP packet executed by the gateway device when a response IP packet from an A / V device in response to a request from an external information processing terminal is received. 8A and 8B are modifications of FIG. 5 and show another flowchart for device search executed by the gateway apparatus in response to a request from the external information processing terminal. FIGS. 9A and 9B are a variation of FIGS. 8A and 8B and show yet another flowchart for device discovery performed by the gateway device. FIG. 10 shows a list of network service discovery information stored in the storage unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal network 50 External network 100 Gateway apparatus 120 Network information provision apparatus 122 Information search part 124 Information analysis and conversion part 126 Information management part 128 Network service transfer information storage part 129 Network service discovery information storage part 130 Network service Transfer unit 220, 240, 260 Audio / video equipment 420, 440 External information processing apparatus

Claims (4)

An IP packet having a header portion and a payload portion via the first and second networks as a first device connected to a plurality of networks having different network segments including the first and second networks A gateway device for transmitting and receiving ,
The gateway apparatus includes a first address for the first network and a second address for the second network,
Information for receiving a first IP packet representing the third search request information resource includes the header portion as the source from the second device address of the third address through the first network Providing means;
In response to the first IP packet representing the search request, the second second IP packet through the network representing a search request for information resources including the header portion of the second address as a source sends, the second through the network, the second the fourth of the first information including the address of the third device represents the available resources of the third device on the network Search means for receiving a third IP packet including a resource identifier in the payload portion ;
Storage means for storing the third address, the fourth address and the first resource identifier associated with each other,
With
Wherein the information providing means reads said first resource identifier from the storage unit, the second resource for the first network a first resource identifier read the including the first address rewriting the identifier, where the first information rewriting the fourth address in the resource identifier to the first address, then the second resource identifier the payload portion includes and the third a fourth IP packet including the header portion of the address as a destination via the first network transmits to the second device,
Furthermore, the said gateway device via said third fifth first network an IP packet including the header portion of the first address as the destination includes the header portion as the source of the address of the when receiving from the second device, the second network including the header portion of the fifth and the fourth address comprising the header portion of the IP packet as the source of the second address as the destination sixth rewritten IP packet, where the said fifth said third of said first address rewrite the address in the second address and the first 5 packets in a packet of use rewriting the fourth address, then immediately transferring means for transferring the IP packet of the sixth to the third device having a desired information resources via said second network Characterized Rukoto, gateway device. A gateway device that transmits and receives IP packets having a header portion and a payload portion via the first and second networks as a first device connected to at least first and second networks having different network segments. Because
The gateway apparatus includes a first address for the first network and a second address for the second network,
Sends IP packets representing the search request information resource includes the header portion as the source of the second address via regular the second network, via the second network, the first search means 2 of the containing addresses of available devices information resource identifier represents the available resources of the available devices in the network receives a response IP packet including the payload portion,
Said address of said available devices, storage means for storing in association with each other and the information resource identifier,
Information for receiving a first IP packet representing the third search request information resource includes the header portion as the source from the second device address of the third address through the first network Providing means;
With
When the gateway device receives the first IP packet, the information providing unit, in the address and said in association with the resource identifier third list form the address of the equipment available store, the second first resource identifier including a fourth address of the available on the network 3 and the third represents the available resources of the device of the apparatus from the storage means reading, rewriting the first resource identifier read the the second resource identifier for the first network including the first address, the fourth of the time in the first resource identifier It said header portion a rewritten addresses to the first address, then contain and the third address of the second information resource identifier in a list format in the payload portion as a destination of the A fourth IP packet including via the first network transmits to the second device,
Furthermore, the said gateway device via said third fifth first network an IP packet including the header portion of the first address as the destination includes the header portion as the source of the address of the when receiving from the second device, the second network including the header portion of the fifth and the fourth address comprising the header portion of the IP packet as the source of the second address as the destination sixth rewritten IP packet, where the said fifth said third of said first address rewrite the address in the second address and the first 5 packets in a packet of use rewriting the fourth address, then immediately transferring means for transferring the IP packet of the sixth to the third device having a desired information resources via said second network Characterized Rukoto, gateway device. An IP packet having a header portion and a payload portion via the first and second networks as a first device connected to a plurality of networks including first and second networks having different network segments. A program for transferring IP packets for a gateway device for transmitting and receiving ,
The gateway apparatus includes a first address for the first network and a second address for the second network,
Receiving a first IP packet representing the third search request information resource includes the header portion as the source from the second device address of the third address through the first network When,
In response to the first IP packet representing the search request, the second second IP packet through the network representing a search request for information resources including the header portion of the second address as a source sends, the second through the network, the second the fourth of the first information including the address of the third device represents the available resources of the third device on the network Receiving a third IP packet including a resource identifier in the payload portion ;
And storing in the memory in association the third address, the fourth address and the first resource identifier to each other,
Reading said first resource identifier from the memory, rewrites the first resource identifier read the the second resource identifier for the first network including the first address, where the rewriting the fourth address in the first resource identifier to the first address, then the header contain and the third address of the second resource identifier to the payload portion as a destination Transmitting a fourth IP packet included in the portion to the second device via the first network;
Receiving from the second apparatus through the third fifth first network an IP packet including the header portion of the first address as the destination includes the header portion as the source of the address of the when, first 6 IP of for the second network including the header portion of the fifth and the fourth address comprising the header portion of the IP packet as the source of the second address as the destination rewriting the packet, the third rewrite of address to the second address and said in the fifth packets first a the dress fourth address of that time in the fifth packet Rewriting and then transferring the sixth IP packet to the third device having the desired information resource via the second network;
A program that can run to run. An IP packet having a header portion and a payload portion via the first and second networks as a first device connected to a plurality of networks having different network segments including the first and second networks A method of transferring an IP packet in a gateway device for transmitting and receiving ,
The gateway apparatus includes a first address for the first network and a second address for the second network,
Receiving a first IP packet representing the third search request information resource includes the header portion as the source from the second device address of the third address through the first network When,
In response to the first IP packet representing the search request, the second second IP packet through the network representing a search request for information resources including the header portion of the second address as a source sends, the second through the network, the second the fourth of the first information including the address of the third device represents the available resources of the third device on the network Receiving a third IP packet including a resource identifier in the payload portion ;
And storing in the memory in association the third address, the fourth address and the first resource identifier to each other,
Reading said first resource identifier from the memory, rewrites the first resource identifier read the the second resource identifier for the first network including the first address, where the rewriting the fourth address in the first resource identifier to the first address, then the header contain and the third address of the second resource identifier to the payload portion as a destination Transmitting a fourth IP packet included in the portion to the second device via the first network;
Receiving from the second apparatus through the third fifth first network an IP packet including the header portion of the first address as the destination includes the header portion as the source of the address of the when, first 6 IP of for the second network including the header portion of the fifth and the fourth address comprising the header portion of the IP packet as the source of the second address as the destination rewriting the packet, the third rewrite of address to the second address and said in the fifth packets first a the dress fourth address of that time in the fifth packet Rewriting, and then transferring the sixth IP packet to the third device having the desired information resource via the second network;
A method comprising the steps of:

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